Several devices have been observed that have utility in removing solids, liquid fluids and gaseous fluids from liquid fluids such as lubricants, oil, diesel fluids, hydraulic fluid, and the like. Typically, the known devices remove contaminants such as solids by filtration and said devices remove oxidizing or reducing agents through evaporation. U.S. Pat. Nos. showing such devices include 4,289,583, 4,227,969, 4,189,351, 4,006,084, and 4,115,201. U.K. pat. no. 1,424,625 is also of interest.
The devices disclosed in the foregoing patents, and all other devices known to the present inventors, often succeed in removing at least some contaminants from the liquid fluid being reclaimed, but all of the known devices leave at least some contaminants in the fluid. The poorly designed devices leave an unacceptably high amount of contaminants in the fluid. Even the better designed devices have a number of shortcomings.
Typically, the better designed devices include an evaporation plate and chamber area into which the fluid to be reclaimed is introduced, and means are provided for heating the fluid to temperatures between 180 degrees Fahrenheit and 220 degrees Fahrenheit. At pressures below atmospheric pressure, many volatile compounds will evaporate at these temperatures.
However, even these devices are inadequate because they either do not take into consideration a number of variables that affect evaporation, or such variables are considered but not properly controlled.
For example, adequate temperature control has not been observed in the art. Many of the known devices do not provide even heat distribution; this results in uneven evaporation. Some of the devices provide acceptable temperature gradients throughout the liquid, but only if the device is held perfectly level during the reclamation process. Real world conditions seldom permit such ideal laboratory conditions and those reclamation devices that function properly only when held perfectly level have little practical utility.
The earlier devices also lack adequate pressure control within the evaporation chamber and within the filter chamber.
Moreover, the earlier devices are not adapted to handle fluids of differing viscosities; when a wide variety of fluids of differing viscosities are handled by the heretofore known devices, the fluids sometimes burn and the devices eventually become clogged and inoperative.
Moreover, some units lack adequate means for removing volatile organic gases from the evaporation chamber, and include heating elements that are directly exposed to such explosive gases. Needless to say, such devices are dangerous.
Clogged jets are also common in the earlier devices because solid particulate matter is inadequately filtered; the clogged jets lower the flow rate through the chamber and, when coupled with inadequate temperature control, lead to burning of the fluids in the chamber. The art has observed that the fluid burns quite easily because a thin film thereof forms on the walls of the evaporator chamber, but no effective means has heretofore been found to overcome the interrelated problems of clogged jets, reduced flow rates, and burning fluids.
Another less serious but troublesome shortcoming of the heretofore known devices relates to the structural aspect of such devices: they include closure means that are bolted to the canisters that hold the filtration media. Thus, facile replacement of the media is not available.
The prior art, when considered as a whole in accordance with the requirements of law, neither teaches nor suggests better methods and devices for reclaiming industrial fluids. The conventional wisdom is that the art has already reached its highest level of development, and that future developments will be limited to minor refinements of the known devices.